Proposed is a long range project which will be our major effort. The general title of the project is "Plasma Membrane Proteins of Clonal Cell Lines from Differentiated Mammalian Cell Tumors." Our primary effort in inducing differentiated cell tumors has been in neurotumors in mice and rats using chemical carcinogens. We have had success so far in inducing neurotumors in rats from which clonal cell lines have been isolated. In mice, we have not yet obtained neurotumors. Instead, a number of lymphocytic tumors have been obtained from mouse AKR strain, which will also be analyzed. Continued efforts will be made to induce neurotumors in mice by using various carcinogens. We believe that this is a way to make biochemical analyses of the surface specificity proteins of mammalian cells feasible. We plan to look for proteins on the plasma membrane of mammalian cells which may be critical for cell specificity in differentiation and development and for tumorgenicity. Nuclear membrane proteins will also be analyzed by using a similar technique. Specific experiments proposed are: A. Fractionation and characterization of plasma- and nuclear-membrane proteins by two-dimensional gel electrophoresis. B. Induction of tumors, particularly neurotumors, by chemical carcinogens primarily in mice and also in rats, and intensive cloning of a tumor to establish different cell lines. C. Specific I125 labeling of proteins on the outer surface of cells. D. Development of new fractionation methods of membrane proteins.